Electromagnetic device



July 13, 1943. w. A. RAY

- ELECTROMAGNETIC DEVICE Filed Feb. 12. 1940 W/Zl/AM A. QAY,

3nventor;

(Ittorneg Patented July 13, 1943 UNITED-STATES PATENT OFFICE 2,324,109 ELECTROMAGNETIC DEVICE William A. Ray, Glendale, Calli'.

Application February 12, 1940, Serial No. 318,520

1 Clairm (or. 175-436) My invention relates to improvements in elec-= tromagnetic devices of the type which employs a U-shaped core and a pivoted armature cooperable with the ends of said core;

To ensure continued uniform operation of such a device, it is essential that the arms of the core remain relatively unmoved after positioning of the armature with respect thereto, especially when the device is adjusted for maximum sensitivity of operation. When the core is made by bending a bar of iron to U-shaped form, some relative movement of the ends of the arms may occur in time if the core is not thoroughly aged before the device is assembled. Also, when the device is jarred in transportation, or by a fall, there is a tendency for the arms to move with respect to each other, especially when the core is supported only by one of its arms and the other arm carries a heavy energizing coil.

It is therefore an object of my invention to provide simple and effective means for prevent- 1 arms of a U-shaped eiectromagnet core and also for retaining and guiding an'armature therefor.

Other objects and advantages of my invention will be found in the description, the drawing, and

the appended claim.

For complete understanding of the invention reference may be had to the following detailed description and accompanying drawing, wherein:

Figure 1 is a plan view of an electromagnetic relay embodying my invention: I

Figure 2 is a side elevation of the device shown in Fig. l; j

Figure 3 is an enlarged perspective view of the core-holding and armature-retaining means shown in Figsnl and 2: and

Figure 4 is a plan view of the armature shown in Figs. 1 and 2.

In the drawing. the numeral i I indicates a base of insulating material on which is mounted, by a bracket i2, a U-shaped core I! which carries on its free arm ll an energizing coil member I! having leads I! connected to terminals II. Interposed between the bracket i2 and the supporting arm ll of the core II is a portion of a core-holding and armature-retaining member is, of non-magnetic material, shown per se in Fig. 3. The latterly bent portion 2' of this member is provided with a rectangular opening 2i for receiving the end of arm I4 and holding it rigidly with respect to the other arm ll. The shape of the opening 2i is made to conform substantially to the cross section of arm it, but, in practice, some clearance is permissible as the core is preferably formed with its arms slightly spread apart, the member iii, in assembly, forcing them to parallel position so that there is a tension between the outer side ofarm I4 and the engaging edge of the opening 2i.

The end of arm I8 is angularly ground to provide a knife-edge fulcrum 22 for an armature 23,

the lower end portion of which carries a contact element cooperable with a fixed contact screw 24 threaded in a terminal bracket 25. A contractile spring 26 urges the armature away from the end of arm I4 and the contacts apart. A lead 2'1, soldered to the armature, electrically connects the movable contact element to a terminal 28.

The central-part of the bent portion 20 of member 19 is cut away to receive the fulcrum end of arm l8 and also to form an extension 29 which is provided with an opening, the. side edges 30 of which cooperate with notches 3|, formed in the opposite edges of the armature adjacent its fulcrum, to retain and guid the armature. The end of the extension 29 is cut away at 32 to permit insertion oi the armature. Means for securing the end of spring 28 is provided bya portion 33 struck up from the member i8, adjustment of the tension of the spring being accomplished by bending this portion.

This application is a continuation-in-part of my copending application, Serial No. 279,220, filed June 14, 1939, now Patent No. 2,292,477, dated August 11, 1942, wherein'I have shown the coreholding and armature-retaining device of the present application applied to an electromagnetic operator for a pilot valve.

While I have herein shown and described a specific embodiment of my invention, it is obvious that modifications maybe made without departing from the spirit of my invention. I intend therefore that my invention be limited only by the scope of the appended claim.

I claim as my invention:

In a electromagnetic device, a U-shaped core member having a pair of spaced apart arms of substantially equal length, an armature fulcrumed on the end of one of said arms and having a portion cooperable with the end of the other of said arms, a coil surrounding a portion of said other, arm, and a member made from a strip of non-magnetic material extending along a side of said one of said arms and secured thereto, said non-magnetic member having a'portion extending beyond-said fulcrum end'and provided with an opening for guiding only the edges of said armature, said non-magnetic member also having a laterally extending portion provided adjacent its end with an opening for receiving the free end portion of the other of said arms to pre- 

